Dry mouth and bitter mouth with insomnia is a typical symptom of Yin deficiency. Dry mouth, bitter mouth and insomnia are mostly caused by Yin deficiency and internal heat. Yin deficiency of the liver and kidney, liver fire burns the fluid, causing dry mouth; bile fire, causing bitter mouth; disturbed heart and mind, leading to insomnia. In addition to dry mouth and bitterness and insomnia, there may be symptoms such as emotional irritability, irritable heat in the hands and feet (irritability and sultriness), night sweating, dry stools, red tongue with little moss, and a thin pulse (pulse that becomes narrower and thinner and quicker in rate). Treatment should be based on the principle of nourishing Yin. For medication, Zhi Bai Di Huang Wan and Zuo Gui Wan can be chosen. Zhi Bai Di Huang Wan can nourish yin and reduce fire, while Zuo Gui Wan can nourish kidney and tonify yin. The above medicines are not suitable for patients with colds and pregnant women. Avoid cold and greasy food during the use of the drug. Drugs should be taken under the guidance of a physician. In terms of daily diet, pay attention to light diet, can eat black beans, wolfberry, yam and other yin nourishing food. If bitter and dry mouth, insomnia or related symptoms of yin deficiency occur, prompt medical attention should be sought.